Network Probes

Network Probes
The network probes monitor the transfer of information from the MySQL server and clients of all types
over the network. The probes are defined as follows:
net-read-start()
net-read-done(status, bytes)
net-write-start(bytes)
net-write-done(status)
• net-read-start: Triggered when a network read operation is started.
• net-read-done: Triggered when the network read operation completes. The status is an
integer representing the return status for the operation, 0 for success and 1 for failure. The bytes
argument is an integer specifying the number of bytes read during the process.
• net-start-bytes: Triggered when data is written to a network socket. The single argument,
bytes, specifies the number of bytes written to the network socket.
• net-write-done: Triggered when the network write operation has completed. The single
argument, status, is an integer representing the return status for the operation, 0 for success and 1
for failure.
You can use the network probes to monitor the time spent reading from and writing to network clients
during execution. The following D script provides an example of this. Both the cumulative time for the
read or write is calculated, and the number of bytes. Note that the dynamic variable size has been
increased (using the dynvarsize option) to cope with the rapid firing of the individual probes for the
network reads/writes.
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